A breakthrough in fertility science by researchers from Bristol and Mexico has shattered the universally accepted view of how sperm ‘swim’. More than three hundred years after Antonie van Leeuwenhoek used one of the earliest microscopes to describe human sperm as having a “tail, which, when swimming, lashes with a snakelike movement, like eels in water”, scientists have revealed this is an optical illusion. Using state-of-the-art 3D microscopy and mathematics, Dr Hermes Gadelha from the University of Bristol, Dr Gabriel Corkidi and Dr Alberto Darszon from the Universidad Nacional Autonoma de Mexico, have pioneered the reconstruction of the true movement of the sperm tail in 3D. Using a high-speed camera capable of recording over 55,000 frames in one second, and a microscope stage with a piezoelectric device to move the sample up and down at an incredibly high rate, they were able to scan the sperm swimming freely in 3D. The ground-breaking